Lift arm assembly



Nov. 11, 1958 J. BARTON LIFT ARM ASSEMBLY 5 Sheets-Sheet 1 Filed Jan. 28, 1955 M 2 jw fl-\\\\\,\; W fl M\ M W M i 2: 4 M 4 I W, W W ZT A M w M Q a u c a o a o a o a O o o INVENTOR. \74 was 4547-2 071 Nov. 11, 1958 J. BARTON 2,360,099

LIFT ARM ASSEMBLY Filed Jan. 28, 1955 5 Sheets-Sheet 5 flW/es 5472 072 Nov. 11, 1958 J. BARTON 2,860,099

I LIFT ARM ASSEMBLY i Filed Jan. 28, 1955 5 Sheets-Sheet 4 ,7dmea jar a?! Nov. 11,1958 J. BARTON 2,860,099

LIFT ARM ASSEMBLY Filed Jan. 28, 1955 5 Sheets-Sheet. 5

- I 152 1 0 M o 5 I //Z@ I//4 LIFT ARM ASEMBLY James Barton, Detroit, Mich., assignor to F. B. Stevens, Inc. (Michigan) Application January 28, 1955, Serial No. 484,741

Claims. (Cl. 204213) The present invention relates generally to apparatus for electroplating and chemical treatment of metal surfaces. More specifically, the invention relates to a lift arm assembly for use on electroplating machines, which assembly has a novel means of conveying electric current to a basket, barrel or plating frame suspended from the end of the arm.

An object of this invention is to provide a lift arm assembly for an electroplating machine, which arm has a novel means of conveying or carrying current down its length for connection to electrodes (cathodes) situated near the objects to be plated.

Another object is to provide a lift arm assembly which is not electrified per se and which need not be insulated from the machine frame, from the conveyor and the machine drive mechanisms.

Still another important object is to provide a lift arm assembly having an electrical system which can not easily be put out of commission by overheating, by contact with corrosive solutions and fumes, by mechanical injury and other deleterious influences.

Yet another object is to provide an assembly of the type described in which the electrical system is simple to disassemble, inspect and repair.

Yet another object is to provide a lift arm assembly of the type described herein which can be used as a replacement for similar arms already in use without modification of the basic plating machine. Still other objects and advantages of the present invention will be apparent, or will become apparent, in the following detailed description taken in conjunction with the accompanying drawings, in which:

Figure 1 is an end view in perspective of a typical plating machine showing installed thereon a plurality of the lift arm assemblies of this invention;

Fig. 2 is a side view in section of one side of the plating machine of Fig. 1 showing one embodiment of the arm of the invention installed thereon, the section being taken along the center line of the arm;

Fig. 3 is a side view in section similar to that of Fig. 2 but showing a larger, heavier version of the arm lift assembly of this invention;

Fig. 4 is an end view in section of the basket hub of Fig. 2 and its electrical connections, the section being taken along the line 44 of Fig. 2;

Fig. 5 is top view in section of the cathode electrode rail and contact shoe assembly of Fig. 2, the section being taken along the line 5-5 of Fig. 2;

Fig. 6 is a top view, with portions broken away and in section of the top end of the arm of Fig. 2, the figure being viewed as if along the arrow 6 of Fig. 2;

Fig. 7 is a view similar to that of Fig. 6 but showing the top end 'of the arm of Fig. 3, the view being taken between the arrows 7-7 of Fig. 3; and

Fig. 8 is an end view in section of the collector ring and contact shoe assembly of the arm of Fig. 3, the section being viewed generally along the line 8-8 of Fig.- 7.

Referring now to the accompanying drawings, and

United States Patent 0 2,860,099 Patented Nov. 11, 1958 "ice particularly Figs. 1 and 2 thereof, it will be seen that there is illustrated a plating machine of the type utilized for plating of small articles in bulk. For this purpose a quantity of small articles such as bolts, screws, stampings, springs, etc. is placed in a barrel, or basket 10 attached to an arm 12 which carries the basket from one tank 14 to another for the various treatments necessary during plating, meanwhile rotating it to tumble the articles to obtain uniform treatment and plating. The arms 12 are supported on a central machine frame 16 on which is journalled a conveyor chain 18 driven by a drive unit 20. A curved cam rail 22 is provided to lift the arms when they approach a tank Wall, the arms being supported on the cam rail by means of a lift roller 24 beneath the arm. Along the straight sided portions of the machine a long screw drive shaft 26 is provided to engage a worm gear 28 mounted in each of the arms. Rotation of the screw shaft rotates the baskets 10 to impart the desired tumbling action.

Also provided along portions of the straight length of the machine frame or base 16 is a cathode rail or bus bar 30 which engages a shoe 32 on each arm assembly to supply current thereto, the cathode rail 30 being provided only opposite those plating and cleaning stations requiring electrification. The upper end of the arm is supported by a pair of lower chain follower wheels or rollers 33 which fit snugly in a trough-like guide 34 and by a pair of upper chain follower wheels or rollers 36 which rest against the outer surface of a chain protectortrough 38 attached to the top of the machine frame 16. The chain follower wheels or rollers 33, 36 are attached to a square or rectangular frame comprising a pair of vertical arms 40, a horizontal cross piece 42 and a pivot shaft 44. The arms are suspended by a pair of clevis arms 46 journalled on their upper ends on pivot shaft 44 and on their lower end integral with a collar-like ridge on the top end of the arm housing 48. The lift roller 24 is mounted on a shaftSt) journalled in a depending bracket-like extension 52 integral with arm housing 48. In all positions, therefore, the main weight of the arms 12 and the baskets 1t and their contents is borne by the lift cam rail 22, the rollers 33, 36 taking the smaller sideward components of the weight. The arms 12 pivot about shaft 44 when lifted by the curvature of cam rail 22. Connection between the arm and the conveyor chain 18 is effected by a horizontal chain finger 54 attached to cross member 42 and attached to a pin passed through one of the chain links or rollers.

, Thus far the structure described is conventional. Previous arms of this same general type have been so de signed either that direct connection between the contact shoes 32 and the arm housing 48 (i. e. to electrify the entire arm) was effected by short external cables or a cable-like insulated conductor was extended down the center of the arm housing. In the former case, the arm lift rollers 24, the chain follower wheels 33, 36, the chain finger 54 and the worm gear 28 had to be insulated from the machine frame. This was diflicult and, moreover, corrosive solutions and fumes corroded metal parts and broke down the insulation such that shorting occurred. In the latter case, the internal conductor was subjected to moisture, corrosive solutions and heat such that the insulation would swell making it well nigh impossible to withdraw it for inspection and replacement. Moreover, the swelled conductor was apt to stick and be twisted off by rotation of the arm. The arm assembly of this invention eliminates all these difficulties and makes the arm capable of long periods of service without inspection or repair. Disassembly, inspection and repair of the arm of this invention, and particularly of its electrical system, is especially facilitated and maintenance costs are drastically reduced,

Referring now to Fig. 2, it will be seen that the arm housing 48 is provided with a tubular drive shaft 60 journalled therein in two sets of ball bearings 62 and positioned by means of retainer rings 64 on either end. On the shaft 60 the worm gear 28 is secured by means of a key 66. Below the worm gear there is secured to the shaft 60 the hub 68 of the basket 10, the hub being held thereon by the lower retainer ring 64 and a keystock 70. In the center of hollow drive shaft assembly just described there is disposed a solid copper conductor 72 having an integral circular, flange-like lower end 73. The conductor is supported in the drive shaft on the upper end by an insulating bushing 74 and on the lower end by insulating plates 76, 78 and insulating bushings 80. Bolts 82 are passed through the bushings 80, through the flange 84 of hub 68, through the conductor flange 73, a basket flange 85, and through the basket support arms 87 to clamp the lower end of the conductor 72 and keep it in alignment inside drive shaft 60. Insulating washers 84 insulate the bolt heads from the basket support arms 8'7. On the upper end of conductor 72 there is keyed a circular collector ring 86 of copper or other conductive metal which is secured thereon by a lock nut and cotter key assembly 88. As will be seen most clearly in Fig. 6, a pair of carbon contact shoes 90 ride on the outer surface of collector ring 86 to provide a rotary electrical connection when the drive shaft 66 is rotating. The shoes 98 are mounted on shafts or pins 92 journalled in arms 46 in insulated bushings 94, each of the shafts 92 being provided with a compression spring 96 to maintain tight contact between shoes and ring.

As Will be most clearly seen in Fig. 4, electrical connection with the cathode electrodes in the baskets is effected by a dangler cable assembly 98 (Fig. 1) attached to the outside of the basket support of flexible cable ends 188 appearing in Fig. 4. The cable ends 180 are mounted directly on stud-type mountings 102 secured to the underside of conductor flange 73. To permit this a portion of the basket flange 84 and insulator 76 are cut away. Since the flange 73 is integral with conductor shaft 72 and the flange is securely held between the hub 68 and the basket hub or ring 85, there is very little chance for the electrical connections on either end to be twisted off or impaired by corrosive solutions or fumes.

As will be seen most clearly in Figs. 2, 5 and 6, the contact shoes 90 are electrically connected to the bus bar contact shoe 32 by means of a short pair of flexible cables 104, the latter being secured directly to the bus bar shoe 32 by stud bolts 108 through which is passed the shoe adjusting shafts 92 (only one such connection being visible in Fig. 6). The bus bar shoes 32 are mounted on a cross bar 118 supported by a pair of arms 112 extending outwardly from housing 48. The arms 112 are enclosed in springs and so mounted in a collar 114 as to be adjustable as to length. The shoe 32 (Pig. 5) is supported by cross bar 118 on two pins 116 which are freely slideable in and out except for the action of the compression springs 118. The shoe 32 comprises a copper contact portion 128 and an equalizer cap 122 connected to the shoe 120 by a pin 124. The cross bar 110 is insulated from the support arms 112 (and from the arm itself) by a pair of insulating washers 126 and an insulating bushing 128 around each stud bolt 130. The electrical system comprising the cathode track 30, the track contact shoe 32, the shoe connector cables 104, the ring contact shoes 90, the collector ring 72 and the cables 100 are easily disassembled, singly or in combination, for inspection and repair of any of its parts, all without complete disassembly of the arm itself or its removal from the machine. Since the arm itself is not electrified, none of its support rollers need be insulated from the machine frame and the arms are safer to operating personnel who must service and inspect the arms 87, only a pair 106 and, on the other end, to a bracket machine while it is operating. The relatively large cur rent carrying capacity of the central conductor shaft and its collector ring, shoes, etc, result in less waste of electrical energy due to heat generation and permit the operation of the machine with greater current densities.

In Figs. 3, 7 and 8, there is shown a second embodiment of a lift arm assembly adapted for use on a larger, heavier type of machine. As before, the arm has a main housing portion which is supported on a heavy lift roller 142 which follows a lift cam rail 22 attached to the machine frame 16. The lift roller 142 is journalled on a shaft 144 extending through an integral bracket arm 146. It will be noted that the lift roller 142 is located lower down on the arm than was the roller of the arm of Fig. 2. The upper end of the arm is suspended from the machine frame in much the same fashion as is the arm of Fig. 2, the same numerals being applied to corresponding parts. Likewise, a cathode track 30 is attached to a bracket 148 and insulated therefrom by pad 150 of insulating material.

The arm of Figs. 3 and 7 and 8 has a tubular central drive shaft 152 journalled in sleeve-type bearings 154 and provided at the top with a ball thrust bearing 156. Keyed near the upper end of the drive shaft is a worm gear 158 which meshes with a screw drive shaft 26. Since the worm gear is located near the upper end of the arm, the arm housing can extend down to the basket hub to prevent entry of corrosive solutions or corrosive fumes.

On the lower end, drive shaft 152 is supported in another sleeve-type, pressure lubricated bearing 154 and an oil seal 156 is provided to prevent escape of oil which could find its way into the plating tanks. Also keyed on the lower end of the drive shaft 152 is a basket hub 158, a retainer ring 160 being provided to keep it on the shaft.

As in the arm of Fig. 2, a solid copper conductor shaft 162 is supported inside drive shaft 152 by means of an insulating bushing 164 on its top end and by a flange 166 on its lower end which is clamped between the hub 158 and a basket collar 85. As before, the conductor flange 166 is insulated by insulating layers 76, 78 and insulating bushings 81D and washers 84. On the upper end of conductor shaft 152 there is keyed a collector ring 168 having two adjustable carbon contact shoes 170. Cables 172 connect the shoes with a cathode pick-up shoe 32 in the same fashion. The shoe 32 is supported by a pair of pins 116 extended through a cross bar 174 bolted to arms 46 and insulated therefrom by washers 176 and bushings 178. A pair of cables 180 connected to the conductor flange 166 are extended down to connect with the cable dangler assembly 98 shown in Fig. 4. The arm of Figs. 3, 7 and 8 is capable of handling a larger basket and a much heavier load of metal to be plated.

The lift arm assembly of this invention, once installed on the machine, can be readily inspected and many of its parts removed and replaced without disturbing the arm itself. For more serious repairs, the arm can be completely disassembled, and the electrical system, insulation, connections, cables and the like, can be completely and economically replaced, if necessary.

What is claimed is:

1. A lift arm assembly for a plating machine having a conveyor means and guide rails for moving said assembly from station to station, a cam rail for lifting and lowering said assembly into and out of the treating solutions, a drive screw for rotating the said arm assembly and a cathode rail opposite those stations requiring electric current, said assembly comprising a housing portion having a supporting wheel adapted to contact said cam rail, a plurality of support rollers mounted near the upper end of said housing portion and positioned to engage said guide rails, a first electrical contact shoe mounted on said housing portion so as to engage said cathode rail, said contact shoe being insulated from its support and said housing, a tubular drive shaft rotatably mounted in said housing, a worm gear secured to said drive shaft and positioned to engage said drive screw, a conductor shaft mounted inside said drive shaft and separated therefrom by an insulating bushing, a collector ring secured to the upper end of said conductor shaft, a second contact shoe in contact with said collector ring and electrically connected to said first contact shoe and connector means on the bottom end of said conductor shaft and connected to said drive shaft by insulating means.

2. An assembly as defined in claim 1 wherein the drive shaft is provided on its lower end with a hub adapted to support a work container and said conductor shaft is provided on its lower end with a flange adapted to fit between said hub and said container, said hub and said flange being separated by insulating material and secured together so as to rotate as a unit.

3. A lift arm assembly for a rotatable electroplating basket for use in an electroplating machine having a plurality of work stations and conveyor means to move a basket along said work stations comprising a housing, roller means attached to said housing near its upper end for supporting said housing and means on said housing connecting said housing to said conveyor means, a tubular drive shaft journaled in said housing and a plating basket secured to the lower end of said shaft, an electrical conductor insulated from said shaft and fixedly mounted within said shaft so as to rotate therewith, said conductor extending outwardly from the upper end of said housing, drive means to rotate said shaft, a collector ring conductively connected to said conductor on said upper extension thereof, contact means for electrically connecting said conductor to a fixed source of electric power through said collector ring, said conductor having connecting means secured to the lower end thereof to flexibly connect said conductor electrically to articles loosely held in said basket.

4. An electrified arm assembly for supporting a plating barrel of the type which is adapted for use on an electroplating machine having a plurality of work treating stations, a cam rail for lifting and lowering said assembly into and out of said stations and conveyor means for moving a barrel through such work stations, which assembly comprises a housing, means near the upper end of said housing supporting said assembly and pivotally attaching said assembly to said conveyor means, means on said housing adapted to contact said cam rail for causing the lower end of said housing to periodically raise and lower about said pivot as said conveyor means moves said assembly relative to said work stations, a tubular drive shaft rotatably mounted in said housing and extending outwardly from the lower end of said housing, a barrel secured to said extending portion of said shaft, driving means connected to said shaft, a conductor shaft disposed within said drive shaft and electrically insulated therefrom, said conductor being secured to said shaft so as to rotate therewith, a collector ring on the upper end of said conductor shaft, electrical power source means engaging said collector ring, and means electrically connected to the lower end of said conductor shaft for supplying electrical contact with articles to be plated in said barrel.

5. An arm assembly in accordance with claim 4 wherein said means supporting said assembly and pivotally attaching the same to said conveyor includes a pivot shaft, roller means attached to said pivot shaft for supporting said assembly, bifurcated arms attached to said pivot shaft and to said housing, said collector ring being disposed between said arms and resiliently biased means mounted on each said arm slidably contacting said collector ring.

References Cited in the file of this patent UNITED STATES PATENTS 1,028,786 Reid June 4, 1912 1,895,622 Hannon Jan. 31, 1933 2,148,552 Hannon Feb. 28, 1939 2,187,079 Hannon Jan. 16, 1940 FOREIGN PATENTS 459,859 Great Britain Jan. 15, 1937 

1. A LIFT ARM ASSEMBLY FOR A PLATING MACHINE HAVING A CONVEYOR MEANS AND GUIDE RAILS FOR MOVING SAID ASSEMBLY FROM STATION TO STATION, A CAM RAIL FOR LIFTING AND LOWERING SAID ASSEMBLY INTO AND OUT OF THE TREATING SOLUTIONS, A DRIVE SCREW FOR ROTATING THE SAID ARM ASSEMBLY AND A CATHODE RAIL OPPOSITE THOSE STATIONS REQUIRING ELEOTRIC CURRENT, SAID ASSEMBLY COMPRISING A HOUSING PORTION HAVING A SUPPORTING WHEEL ADAPTED TO CONTACT SAID CAM RAIL, A PLURALITY OF SUPPORT ROLLERS MOUNTED NEAR THE UPPER END OF SAID HOUSING PORTION AND POSITIONED TO ENGAGE SAID GUIDE RAILS, A FIRST ELECTRICAL CONTACT SHOES MOUNTED ON SAID HOUSING PORTION SO AS TO ENGAGE SAID CATHODE RAIL, SAID CONTACT SHOE BEING INSULATED FROM ITS SUPPORT AND SAID HOUSING, A LUBULAR DRIVE SHAFT ROTATABLY MOUNTED IN SAID HOUSING, A WORM GEAR SECURED TO SAID DRIVE SHAFT AND POSITIONED TO ENGAGE SAID DRIVE SCREW, A CONDUCTOR SHAFT MOUNTED INSIDE SAID DRIVE SHAFT AND SEPARATED THEREFROM BY AN INSULATING BUSHING, A COLLECTOR RING SECURED TO THE UPPER END OF SAID CONDUCTOR SHAFT, A SECOND CONTACT SHOE IN CONTACT WITH SAID COLLECTOR RING AND ELECTRICALLY CONNECTED TO SAID FIRST CONTACT SHOE AND CONNECTOR MEANS ON THE BOTTOM END OF SAID CONDUCTOR SHAFT AND CONNECTED TO SAID DRIVE SHAFT BY INSULATING MEANS. 